The present invention relates to ink jet printing heads and to the printers using such heads. In particular, the invention relates to an ink jet printing head for a liquid and electrically conductive ink, comprising an electrically insulating container for the ink, having a nozzle for the selective discharge of particles of ink, an electrode in contact with the ink and a counter-electrode adjacent to the nozzle, the discharge of ink being caused by an electrical voltage pulse between the counter-electrode and the electrode.
In the known heads of the above-indicated type, the container is connected by means of conduits to a larger-capacity tank which is disposed some distance from the printing location. In the case of printers in which the head is mounted on a movable carriage, the tank is disposed on the fixed part of the machine and is connected to the container by way of flexible conduits of substantial length. Pump means are required for conveying the ink from the tank to the head, so that the printer is expensive to produce and complicated in operation.